Process of amplifying electric currents.



Patented Gat. 30, |900. y.1. B. BAKER.' PROCESS 0F AMPLIFYING ELECTRIC CUBRENTS.

(Application tiled Nov. 23, 1899.)

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(No Model.)

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Patented oct. 30, |900. J. B. BAKER.

PROCESS QF .AMPLIFYING ELEC-[mic GURRENTS.

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A( No Model.)

THE Nmws Permis co.. Fuoroujfuo., wAsnmnToN. n, c.

N0. 660,6l3. Patented C. 30, |900. J. B. BAKER. PROCESS 0F AMPLIFYING ELECTRIC CURRENTS.

(Application filed Nov. 23,y 1899.)

K(N0 Model.)

No. 660,6l3. Patented Oct. 3o, |900.

J. B. BAKER. PROCESS CF AMPLIFYING ELECTRIC CURRENTS.

A: (Application led Nov. 23, 1899.) (N0 M ndel.) 4 Sheets-Sheet 4.

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UNITED STATES PATENT Osmosi.

JOSEPH B. BAKER, OF NEi/VTON, MASSACHUSETTS.

PROCESS OF AMPLIFYING ELECTRIC CURRENTS.

SPECIFICATION forming part of Letters Patent No. 660,613, dated October 30, 1900.

Application filed November 23, 1899 Serial No. 738.066. (No model.)

To all whom it may con/cern.-

Be it known that I, JOSEPH B. BAKER, a citizen of the United States, and a residentof Newton, in the county of Middlesex and State of'Massachusetts, have invented certain new and useful Improvements in Processes of Amplifying Electric Currents, of which the following is a specification.

Figure lis a diagram of a hypothetical field of force. Fig. 2 is a diagram of a unipolar ield of force. Fig. 3 is a-perspective schematic view of a unipolar motor of the common or Faraday type. Fig. 4 is a diagram of a bipolar field of force. ll are each'diagrams of diierent apparatuses which may be used to carry out the process.

of my invention.

Let us imagine a number of lines of force confined to a single plane and all radiating uniformly from a com mon central point-such a field of force, for instance, as is represent-ed in Fig. l. Let us also imagine that we have a' straight electrical conduct-or or piece of copper wire @,Which is perpendicular to the plane of the lines of force and which revolves about their central or radiating point o, thus describing a cylinder having its axis passing through o as its center. Itis well known and can be readily understood that in such event there is generated in the wire ct an electronictive force which is constant in amount and direction for each and every position of the wire. As the iield is entirely uniform, as the wire cuts each element of the field at exactly the same angle, and as the velocity of rotation is uniform, the electromotive force impressed upon the wire must be constant and lthe same for any circular point about the center o. The wire is always perpendicular to the particular line of force which it cuts, and the direction of motion of the wire at such instantis also perpendicular to such line of force.

A set of lines of force such as has just been described is realized, so far as practical purposes are concerned, at the pole of a bar-magnet. Fig. 2, for instance, illustrates a longitudinal section through the lines of force of a bar-magnet; but inorder to get a proper idea of the lines of force about such pole as they exist in space we must imagine the diagram rotated about the central axis NS, when wc see that'in each plane perpendicular to the Figs. 5, 6, 7, 8, 9, I0, and` axis there are found lines of force radiating from a central point, just as in Fig. l. It is plain, therefore, that-if a copper wire a lying lwithin'this field of force be rotated at a uniform rate, so as to remain always parallel to the axis of the magnet and at the same distance therefrom, there will be generated vin the wire an electroinotive force which is constant in amount and the same for every position of the wire during its rotation. The wire cuts all of the lines of force which it meets substantially at right angles, and the direction of motion of the wire is at right angles to such lines of force which at the instant in question are cut by the wire.

The eld of force which I have just described has long since been utilized by Faraday inconstructing an electric motor, one form of which is indicated in Fig. 'lhere is an annular mercury-bath b, in the center of Which is mounted the upper pole of a barmagnet N. Oonducting-wiresctctare mounted to rotate on a pivot c, and the connections are such that a current may pass from the binding-post c to the pivot c through the conducting-wires a a in parallel to the mercurybath and binding-post b. If then the conductors a are rotated by mechanical power about the magnet N, it is plain that a current will be generated which may be assumed as passing downwardly through each limb of the conductors a into the mercury-bath, and thence to the binding-post connected therewith. On the other hand, if the conductors a be not rotated by mechanical power, but a bath, the reactions set up will be such as to cause a uniform rotation of the conductors a.

The type of a field of force which I have just been describing, and which has been called the unipolar type, is essentially distinct from the typeof field of force which I have indicated in Fig. 4of the drawings, and which may be called the bipolar type. The ligure shows a field-magnet wound so as to produce a north and south polarity, respectively. The lines of force joining these poles are approximately parallel and are indicated by the dotted lines. If we assume a Wire o, perpendicular to the plane of the figure to be revolving aboutthe central axis o, it is clear current be passed up through the magnet and down through the conductors d and mercury- ICO erated so long as the field .as a Wholeremains that the relation of this wire to the lines of force changes from instant to instant. In the position Shown the Wire o'. is cutting no lines of force. Farther on in its course the Wire will be cutting the lines of force at an acute angle, and when the Wire has reached the position which is ninety degrees from that shown it will be cutting the lines of force at right angles. Farther on it will be cutting the lines of force in an opposite sense, so that we see that-the Wire a. is the seat of an electromotive force which is not constant, but which is varying `from moment to moment and which' changes in direction twice for each revolution of the Wire.

Now the object of my invention is to repeat gradually Varying or alternating signalingcurrents and, as aspecial case, telephonie currents, which, in other Words, means that I propose either to amplify the gradually-varying such a lnanner that the electromotive forcesA which are generated in the conductor are similar in sign and equal in amount forevery position of the conductor Within the fieldthat is to say, so long as the field remains unchanged as a Whole the electromotive force induced in the conductor will be independent of the position of the conductor in the field. If, on the other hand, the field as a Whole grows more dense or less dense or changes in sign, as it would if it be generated in a Whole or in part by an alternating or varying current, it is equally clear that We may so rotate a conductor therein as to have the electromotive force induced in the conductor at any given instant of time proportional to the density of the field and the sign of the electromotive force determined ,by the sign of the field, so that the electromotive Now my invention consists, broadly stated,

yin the process of amplifying or generating amplified gradually-varying harmonic or alternating signaling-currents by causinga conductor to so move in a magnetic field generated in Whole or in partbya signalingcurrent that during every position inthe motion of the conductor electromotive forces similar insign and equalin amount are genunchanged, variations in the sign or amount of the electromotive force generated in the conductor being determined solely by varia;

as a whole, but the electromotive force generated in each element of the system is the force generated in the system of cond uctors. l'

same at leach point of the motion so long as the field remains unchanged as a Whole, variations in the density of the field vcausing variations in electromotiveforces which are exactly proportional thereto in sign and amount and which are independent of the position ofthe moving conductor in the field.

More specifically stated, my invention consists in the process of amplifying gradually varying or alternating signaling-currents or of generating amplified varying currents by continuously moving a conductor in a mag# netic field, so that the motion of the conductor is at each point of its path'substantially at right angles to the lines of force which are cut by the conductor at this point. thus be seen that by utilizing a varying signaling-current to generate a magnetic field, preferably of the unipolar type, which I have above described, and by causing a conductor to move continuously within this field in the manner above poiuted'out I can cause to be generated. Within this conductor an electromotive force, and in consequence a current which shall at each and every instant. of time be exactly proportional to the strength of the field generated by the varying current, and that I can thereby generate a largely amplified or reinforced signaling current Without in any way distorting it or changing its character.

`Naturally my invention has a most advantageous application in repeating telephone'- currents, for the reason, as stated above, that the variations in the sign and amount of' the electromotive forces generated in the moying conductor are determined by and are exactly proportional to the variations in sign and amount of the magnetic field generated by the telephone-currents to be repeated. There is therefore no substantial distortion of any kind in the repeated telephone-currents, which are merely amplied pictures of the original currents which generated them.

- I shall therefore especially claim this feature.

In order that my process may be more fully understood, I proceed to describe a number of apparatuses, each of which may be used in order to carry the process into`effect.

In Fig. 5 I have shown the upper pole N of a permanent magnet on which is mounted a mercury-cup e. This pole N-is surrounded by a telephone-coil t. A shaft g, driven by a pulley g andbelt g, is mounted in bearings f. These bearings may be supplied With ball-races (not shown) or may be of other special design for the purpose of diminishing friction.y On the shaft gis mounted a It Will IOD IIO

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yoke-armature ZL, which may have two or more arms, symmetrically disposed, dripping into an annular mercury-trough t'. From the axis of this armature there projects a conducting-pin Zz' into the mercury-cup e. The armature h must naturally be made of some good conductor, such as brass or copper.

The pole N of the bar-magnet creates a field of force of the unipolar type above described, and the construction and arrangement of the yoke-armature are such that in its motion it continually ents the lines of force, due to the pole N, at right angles. If. then, the armature be revolved uniformly by the belt and pulley, a current will be generated which may be assumed as passing from the linewire Z to the mercury-cup e up through the pin h and down through the arms ofthe yoke-armature h into the mercury-trough t and out to line Z. fully pointed out, will be equal in strength for each position of the armature during its rotation. If now a varying signaling telephone-current be passed through the telephone-coil t, the magnetic eld will be changed by an amount which is proportionalto the strength of the varying current. This change in the strength of the magnetic field will correspondingly change the current flowing through the yoke armature, such. current strength not depending upon the position of the yoke-armature at any point of its revolution, but simply depending on the strength of the varying current, the velocity of rotation being constant. It will be seen, therefore, that there will be generated in the circuit of the yoke-armature a varying signalling or telephone current similar in all respects to the current in the coil, but greater in intensity, and such current may be titilized in any known Way. Thus, for instance, the currents in the telephone or signaling coil may be the Weak currents coming from a distant station, and the currents in the yokearmature may be sent to a station farther on, since they have been strengthened. The apparatus of Fig. 5 thus acts as a relay for transmission in one direction only.

It is manifest that instead of rotating the yoke-armature by mechanical power, in which case the pole N need not beA permanently magnetized, I may send a constant current through the circuit of this armature from a constant source, such as a battery, by which means the yoke-armature will be set into rotation bythe reaction of the currents therein on the magnetic field, as was explained above in connection with the Faraday nnipole inotor. The change in the intensity of this current by the current in the telephone-coil will take place as before.

The construction and operation of the apparatus shown in Fig. 6 will be clear withoutA much further detailed explanation. There cury-trough.

This current, as has beenl magnet, and the same annular mercury-bath 'L'. So, too, there is the same shaft g, mounted in bearings j' and carrying an armature h. This armature, however, is a cage or laminated cylinder having an annular brass contact h5 at its lower end dipping into the mernite number of armatures, such as shown in Fig. 5. The operation of the apparatusis precisely that ascribed to Fig. 5. I may merely add that when the armature is driven by mechanical power it is not essential thatthe bar should be permanently magnetized.

'In such case the entire current induced in q. On this shaft g there is mounted a drum 71,4, which is supplied with a helical groove.

There is a unipole N, mounted within this drum,which carriesatelephone-coil. Within the helical groove in the drum is placed a helical conductor h5, connecting with the shaft g at the upper end and with an annulus 71,6 at the lower end. passes through the contact hw to the shaft g, the helical conductor h5, the annular conductor h6, and the ball-bearings k7, to a stationary conductor hs. The helical conductor h5 thus rotates bodily in the unipolar field and has developed in it an electromotive force composed at any inst-ant of two parts-namely, the electromotive force due to the speed of rotation and strength of the field acting on a simple wire rotated parallel to the axis of the magnet and constituting the magnetic projection of the helix, as it is called in the text-books, and the elect-romotive force due to the mutual induction of the signaling or telephone coil on the helix constituting the armature conductor. From this it will be seen that a weak varying-signaling or telephone current passing into the telephone-coil t will by its action upon the magnetic field of t-he unipole generate currents of an amplified character in the line Z Z.

The construction of Fig. 8 embodies a signaling or telephone coil t, surroundinga unihelical conductor by the signaling or telephone coil is transmitted by induction to the secondary coil j and thence to line Z Z. The Wires may be kept from crowding together at the center of the drums by means of stationar)1 guide-pieces holding the. parallel wires apart and guiding them in fixed planes.

The construction of `Fig. 9 embodies'two It acts, in effect, like an infi- The electric circuit IOC IOS

separate unipoles N S, each surrounded by a drum h4 driven as above described. vSignal- 3 D trode fr'.

ing o r telephone coilstsurround the unipoles. There is an endless conductor h on each of the drums h4. Rotation being imparted to the drums and the conductors Wound thereon in any suitable manner, the electromotive forces developed in the'coils Will at each instant be in opposite directions in the endless conductor. It Will be apparent, therefore, that current may be taken from the Wires h Izby means of the sliding contacts 72,10 h1", the current being transmitted to the main line Z Z by means of an induction-coil L, as shown.

In Fig. l I have shown a unipole N, surrounded by a telephone-coil tand a ring-elec- 'lhe shaft g, mounted in bearingsf and rotated as before, carries an electrode r. Current from a dynamo or battery u is passed through the retardation-coils R R and thence through the shaft g to the electrode r and as shown.

. as shown.

across the airspace to the ring-electrode r. The arc maybe rotated bya belt and pulley, The action of the varying iield produced by the telephone-coil upon the arc conductor traversing the lines of force of this field at right angles will in all essential respects be the same as was described above for other types of conductors, and reinforced or magniiied telephone-currents will be sentto the line Z l by means of the induction-coil L,

By this type of construction, embodying a moving arc, the attainment of a high speed is possible, and at. the same time I utilize an effective form of moving contact.

The construction ot Fig. 11 diiers from lthat shown in Fig. IO-namely, in the fact that the belt and pulley for rotating the electrode are dispensed with, the arc being rotated by means oi" its reaction against the magnetic field of the unipole, which is excited for this purpose by an exciting-coil e. Additionally the rotating arc isinclosed by an infusible tube fr51 to prevent any possible rupture of the arc by centrifugal force.

I call attention to the fact thatthe sliding contact h1@ in Figs. 7 and l0 bears on the shaft g at a point of little or no motionof the shaft. This is especially important in the construction of Fig. 10, since were the contact hw ata point of much motion of the armature a principal advantage 'of the use of the electric arc would be rendered of no eiect. Suitable provisions Will be made against losses by eddycurrents in the mercury-troughs, annular contacts, &c.

I have illustrated theseveral types of apparatus Which I have just described in order to explain the principles of my invention and to show how it may be carried into effect.

Will be plain that my invention is not'limited to any specific for-m of apparatus, but covers the process which I have above defined. So, too, it Will be readilyy apparent that many other types of apparatus maybe devised which shall carry out my process, those above described having been merely described by Way of example. I believe, however, that I have described a suftlcient-lyflarge number of types of apparatus to make thefscop'e of my invention and the lines along which it may be developed clear. I need hardly' say that `I am not in this application concerned with any details of the apparatus, and as they will be reasonably clear to a skilled Workman I have not described them.

In each of the apparatuses which I have shown it Will be seen that during every posi= -tio-n in the motion of the moving conductor electromotive forces are generated therein which are determined solely by the density and sign of the whole magnetic field at any `given instant, and not by the position of the `right angles to each other or substantially so.

It may be well to again state if I employ a system of moving conductors instead of a single conductor that the same remark is true of each element of the system of conductors, vand not merely of the system of conductors -as a Whole.

What I claim is l. The process of generating amplified varying signaling-currents which consists in causing a conductor to so move in a magnetic Ifield,vvhich is generated in Whole or in part-by .the varying signaling-current, that the electromotive force generated in the moving conductor is independent of the position of the Iconductor Within the magnetic field, substan-` tially as described.

2. The process of generating amplified varying signaling-currents Which consists in causing a conductor to so move in'a magnetic teld, which is generated in Whole or 1n part bythe varying current, that the electromotive force generated in the conductor is determined solely by variations in the density or sign of the magnetic field, taken as a Whole, and not by the position of the conductor Within the field, 'substantially' as described.

f 3. The process of generating amplified varying signaling -currents which consists in causing a conductor to so move in a magnetic field, whichVr is generated in Whole or in part by the varying signaling-current, that the conductor, its direction of. motion and the line of force which is cut shall at all times be each at right angles to the others, substantially as described;

4. The process of generating amplified varying signaling-currents which consists in causing a conductor to so move in a unipolar magnetic field, generated in Whole or in part by the varying currents that the conductor and its line of motion shalleach be at all rool IIO

times at right angles to each other and the line of force which they cut, substantially as described.

5. The process of generating amplified telephone-currents which consists in causing a conductor to so move in a magnetic field, Which is generated in Whole or in part by a telephone-current, that the electromotive force generated in the moving conductor is independent of the position of the conductor Within the magnetic field, substantially as described.

6. The process of generating amplified telephone-currents which consists in causing a conductor to so move in a magnetic field,

which is generated in whole or in part by a telephone current, that the electromolive force generated in the conductor is determined solely by Variations in the density or sign of the magnetic eld, taken as a Whole, and not. by the position of the conductor Within the field, substantially as described.

7 The process of generating amplified teleis cut shall at all times be each at right angles to the others, substantially as described.

8. The process of generating amplified telephone-currents which consists in causing a conductor to so move in a unipolar magnetic field, generated in whole or in part by the telephone-cu rrents4 that the conductor and its line of motion shall each be at al1 times at right angles to each other and the line of force which they cut, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

JOSEPH B. BAKER. 

